In modern internal combustion engines, in particular those having direct fuel injection, it has been attempted to positively influence the mixture preparation in the combustion chambers in order to achieve optimum conversion of the injected fuel into mechanical energy. In this connection, a comparatively high turbulence of the air charge (“charge motion”) within the combustion chamber is favorable. An increased charge motion or turbulence has a positive impact on the mixture preparation and reduces the exhaust gas emissions.
In order to adjust the motion of the air charge within the combustion chambers, a specific actuator is present in the air intake system in many internal combustion engines, which influences the flow rate of the drawn-in air or of the drawn-in air-fuel mixture by unblocking a variable cross section. Such an actuator is known as a charge motion flap, tumble valve, or swirl valve.
In some countries, it is required by law to monitor the function of the charge motion flap (tumble flap) using OBD (“onboard diagnosis”). In this connection, it is tested if an actual position of the charge motion flap corresponds to a setpoint position required by an engine controller. To this end, the charge motion flap has formerly been coupled to at least one position sensor, which reports the actual position of the charge motion flap to the engine controller. Switch contacts at the end positions of the charge motion flap or potentiometers for continuous recording are known.
An object of the present invention is to refine a method of the type described above so that the internal combustion engine may be manufactured as economically as possible.